Know about Pluto Know about the Asteroids Know about Comets Comprehend the Oort Cloud and Kuiper Belt Asteroids and Kuiper Belt Objects

The Discovery of Pluto Percival Lowell predicted the existence of an additional planet in 1905 Clyde Tombaugh used a device called a blink comparator, spotting the “jump” of a tiny dot on a photograph on 18 Feb 1930

Pluto’s Orbit and Atmosphere Pluto’s orbit is eccentric Averages 40 Aus from the Sun, but it ranges from 30 units to 50 units An Astronomical Unit, or AU, is the mean distance between the Earth and the Sun, about 93 million miles A Parsec is also a measure of distance, roughly (3.26 LY or 19 Trillion Miles)

Pluto’s Orbit and Atmosphere Pluto has an atmosphere, but not year-round At perihelion it “warms up” At aphelion it receives so little solar energy that its surface is below the temperature at which methane freezes

Asteroids The asteroid belt – the region between Mars and Jupiter where most asteroids orbit Jupiter’s gravitational pull has created gaps in the asteroid belt at 2.50 AU and 3.28 AU

The Origins of Asteroids Astronomers once thought that asteroids were the remains of a planet that had exploded Explanation that seems more plausible today: asteroids are simply primordial material that never formed into a planet Jupiter’s gravity keeps pulling on objects in the asteroid belt and stirring them up

Project Dawn

Comets’ Predictable Orbits Around the Sun In 1705 Halley boldly predicted the comet’s return in 1758 On Christmas night of 1758, Comet Halley appeared in the sky Scientists have traced Halley sightings back to 239 BC

A Comet’s Three Main Parts A comet consists of a head and a tail 1. Head is made up of a nucleus—the solid core of a comet—and a coma 2. A coma is the part of a comet’s head made up of diffuse gas and dust 3. The tail of a comet is the gas and/or dust swept away from the comet’s head

The Shell of Comets Surrounding the Solar System In 1950 Oort revived an idea that in a space far beyond Neptune’s orbit, a great number of comets orbit the Earth Oort cloud - a theoretical sphere, between 10,000 AU and 100,000 AU from the Sun, containing billions of comet nuclei

The Small Band of Comets That Make Up the Kuiper Belt In 1951 Kuiper proposed a second, smaller band of comets within the Oort cloud The Kuiper belt is a disk- shaped region beyond Neptune’s orbit, 30 AU to 1,000 AU from the Sun and the presumed source of short-period comets

Meteors vs. Meteorites Meteor – a streak of light in the sky caused when a rock particle falling to Earth is so heated by friction with the atmosphere that it emits light Fireball – an extremely bright meteor Object that causes the meteor is a meteoroid Meteorite is an interplanetary chunk of matter that has struck a planet or a moon

Know about Pluto Know about the Asteroids Know about Comets Comprehend the Oort Cloud and Kuiper Belt Asteroids and Kuiper Belt Objects